I just switched over to playing Galactic Civilizations from Endless Legend and I have to say THANK YOU for such an awesome game (It's much easier to play than GCiv2 for me!).
I already love GCiv3, but there is ONE feature that EL has that GCiv3 does not have, and that's what I call "right-click-dismissal" of empire management screens.
To me, (being a "mouse guy") it's kind of a big deal, so let me explain why:
Essentially, this feature would make management screens go away with a simple right click anywhere inside the current active window instead of having to go to the lower right to click the [Done] button. I have checked almost all of your management screens and as far as I can see there are NO right click mouse event mappings on ANY of those screens so this would be totally easy (I think) to put into the game. All you have to do is map right-click event(s) in each of the management screens to the code contained in the [Done] button push event code. That's it! It would be copying and pasting a few lines of code.
Then, you could map these right click captures to a flag set in the main UI so that people can turn this feature on or off, globally. That would take a bit more time, but I still think it would be dead easy.
Coming from Endless Legend, I was stunned that you hadn't implemented a similar feature in GCiv3 because just adding that right click option really speeds up game flow and you don't have to worry about clicking the "done" button every time you want to leave a management screen. (I'm a mouse guy, not a keyboard guy, admittedly).
I freely admit that it was a bit weird to get used to this feature at first (Pandora: First Contact also has a similar feature, except in that game, it's left clicking on the game map that makes the management interface go away. Same concept, different button), but once you get the hang of it, you will wonder how you ever lived without it! Seriously. Try it. Put it in and play the game and play a few rounds to get used to it. I'll bet you say "Oh, my God! Why didn't I think of this?"
Adding this "right-click-dismissal" actually allows you to go through the management screens MUCH FASTER because you can keep your mouse in the upper left corner and just fly through the screens with a few flicks of the wrist. Right now, you have to go to all the way the upper left to bring up a management screen, and then all the way to the lower right to get rid of it. I have a 27" screen running at 2560x1440 so, to me it was like taking a step backwards in time to previous 4x games that didn't have this feature.
I would certainly appreciate this feature be added and I convinced that a lot of other people would love it too!
Finally, since this is just a code hack you wouldn't have to change anything with your established UIs except for the "on off" button in the UI options.
Thanks for reading!